Lies, and the lying liars who tell them

Ok, so I stole that...

Everyone in the world lies at some point, let's face it. If you always told the truth, you'd probably get punched in the nose a lot, and the human race would die off because sex would cease to happen. My job exposes me to a multitude of fibbing, and of course, like anyone else, I get (and to be fair, give) my share of BS'ing.

However-what is an acceptable lie, and what goes beyond the pale?

Here's my opinion, that is probably stupid and ill-informed, as I'm sure someone will e-mail me and tell my I'm wrong.

1) Lies for entertainment value, or "fishing stories". Who cares? If it enhances a story, is any harm really done? I mean, yeah, its BS, but no one is hurt if an embellishment or two is thrown in.

2) Lies to hide something. This is tricky. Ultimately, the answer comes down to: Is something being hidden that would cause hurt or harm, and that will NOT be found out unless you open your big mouth, and that no one is hurt by not being told it? In that case, it's an acceptable lie. An example might be that you know a friends recently deceased (and well loved) spouse, was actually planning on dumping said friend in a divorce when the car wreck happened-nothing is gained by you opening your big mouth.
If however, it is a lie being told to hide something, that is merely putting off the inevitable, then that's just throwing wood onto what will eventually be a fire. "No, that child in the paternity suit isn't mine dear, I promise" would be a fine example!

3) Backstabbing accusations. well, that's just wrong, isn't it?

4) Lies of omission: OK, here's where I get in trouble. When does not volunteering unasked for information cross the line into being devilishly dishonest? Right here, right now, I will confess to this one. If asked directly, I will answer pretty much any question thrown at me, and do my level best to do so honestly. But, sometimes you just have to know the right question to ask.